mm/debug_vm_pgtable.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * This kernel test validates architecture page table helpers and
   4  * accessors and helps in verifying their continued compliance with
   5  * expected generic MM semantics.
   6  *
   7  * Copyright (C) 2019 ARM Ltd.
   8  *
   9  * Author: Anshuman Khandual <anshuman.khandual@arm.com>
  10  */
  11 #define pr_fmt(fmt) "debug_vm_pgtable: [%-25s]: " fmt, __func__
  12
  13 #include <linux/gfp.h>
  14 #include <linux/highmem.h>
  15 #include <linux/hugetlb.h>
  16 #include <linux/kernel.h>
  17 #include <linux/kconfig.h>
  18 #include <linux/mm.h>
  19 #include <linux/mman.h>
  20 #include <linux/mm_types.h>
  21 #include <linux/module.h>
  22 #include <linux/pfn_t.h>
  23 #include <linux/printk.h>
  24 #include <linux/pgtable.h>
  25 #include <linux/random.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/swap.h>
  28 #include <linux/swapops.h>
  29 #include <linux/start_kernel.h>
  30 #include <linux/sched/mm.h>
  31 #include <linux/io.h>
  32
  33 #include <asm/cacheflush.h>
  34 #include <asm/pgalloc.h>
  35 #include <asm/tlbflush.h>
  36
  37 /*
  38  * Please refer Documentation/vm/arch_pgtable_helpers.rst for the semantics
  39  * expectations that are being validated here. All future changes in here
  40  * or the documentation need to be in sync.
  41  */
  42
  43 #define VMFLAGS (VM_READ|VM_WRITE|VM_EXEC)
  44
  45 /*
  46  * On s390 platform, the lower 4 bits are used to identify given page table
  47  * entry type. But these bits might affect the ability to clear entries with
  48  * pxx_clear() because of how dynamic page table folding works on s390. So
  49  * while loading up the entries do not change the lower 4 bits. It does not
  50  * have affect any other platform. Also avoid the 62nd bit on ppc64 that is
  51  * used to mark a pte entry.
  52  */
  53 #define S390_SKIP_MASK          GENMASK(3, 0)
  54 #if __BITS_PER_LONG == 64
  55 #define PPC64_SKIP_MASK         GENMASK(62, 62)
  56 #else
  57 #define PPC64_SKIP_MASK         0x0
  58 #endif
  59 #define ARCH_SKIP_MASK (S390_SKIP_MASK | PPC64_SKIP_MASK)
  60 #define RANDOM_ORVALUE (GENMASK(BITS_PER_LONG - 1, 0) & ~ARCH_SKIP_MASK)
  61 #define RANDOM_NZVALUE  GENMASK(7, 0)
  62
  63 struct pgtable_debug_args {
  64         struct mm_struct        *mm;
  65         struct vm_area_struct   *vma;
  66
  67         pgd_t                   *pgdp;
  68         p4d_t                   *p4dp;
  69         pud_t                   *pudp;
  70         pmd_t                   *pmdp;
  71         pte_t                   *ptep;
  72
  73         p4d_t                   *start_p4dp;
  74         pud_t                   *start_pudp;
  75         pmd_t                   *start_pmdp;
  76         pgtable_t               start_ptep;
  77
  78         unsigned long           vaddr;
  79         pgprot_t                page_prot;
  80         pgprot_t                page_prot_none;
  81
  82         bool                    is_contiguous_page;
  83         unsigned long           pud_pfn;
  84         unsigned long           pmd_pfn;
  85         unsigned long           pte_pfn;
  86
  87         unsigned long           fixed_pgd_pfn;
  88         unsigned long           fixed_p4d_pfn;
  89         unsigned long           fixed_pud_pfn;
  90         unsigned long           fixed_pmd_pfn;
  91         unsigned long           fixed_pte_pfn;
  92 };
  93
  94 static void __init pte_basic_tests(struct pgtable_debug_args *args, int idx)
  95 {
  96         pgprot_t prot = protection_map[idx];
  97         pte_t pte = pfn_pte(args->fixed_pte_pfn, prot);
  98         unsigned long val = idx, *ptr = &val;
  99
 100         pr_debug("Validating PTE basic (%pGv)\n", ptr);
 101
 102         /*
 103          * This test needs to be executed after the given page table entry
 104          * is created with pfn_pte() to make sure that protection_map[idx]
 105          * does not have the dirty bit enabled from the beginning. This is
 106          * important for platforms like arm64 where (!PTE_RDONLY) indicate
 107          * dirty bit being set.
 108          */
 109         WARN_ON(pte_dirty(pte_wrprotect(pte)));
 110
 111         WARN_ON(!pte_same(pte, pte));
 112         WARN_ON(!pte_young(pte_mkyoung(pte_mkold(pte))));
 113         WARN_ON(!pte_dirty(pte_mkdirty(pte_mkclean(pte))));
 114         WARN_ON(!pte_write(pte_mkwrite(pte_wrprotect(pte))));
 115         WARN_ON(pte_young(pte_mkold(pte_mkyoung(pte))));
 116         WARN_ON(pte_dirty(pte_mkclean(pte_mkdirty(pte))));
 117         WARN_ON(pte_write(pte_wrprotect(pte_mkwrite(pte))));
 118         WARN_ON(pte_dirty(pte_wrprotect(pte_mkclean(pte))));
 119         WARN_ON(!pte_dirty(pte_wrprotect(pte_mkdirty(pte))));
 120 }
 121
 122 static void __init pte_advanced_tests(struct pgtable_debug_args *args)
 123 {
 124         struct page *page;
 125         pte_t pte;
 126
 127         /*
 128          * Architectures optimize set_pte_at by avoiding TLB flush.
 129          * This requires set_pte_at to be not used to update an
 130          * existing pte entry. Clear pte before we do set_pte_at
 131          *
 132          * flush_dcache_page() is called after set_pte_at() to clear
 133          * PG_arch_1 for the page on ARM64. The page flag isn't cleared
 134          * when it's released and page allocation check will fail when
 135          * the page is allocated again. For architectures other than ARM64,
 136          * the unexpected overhead of cache flushing is acceptable.
 137          */
 138         page = (args->pte_pfn != ULONG_MAX) ? pfn_to_page(args->pte_pfn) : NULL;
 139         if (!page)
 140                 return;
 141
 142         pr_debug("Validating PTE advanced\n");
 143         pte = pfn_pte(args->pte_pfn, args->page_prot);
 144         set_pte_at(args->mm, args->vaddr, args->ptep, pte);
 145         flush_dcache_page(page);
 146         ptep_set_wrprotect(args->mm, args->vaddr, args->ptep);
 147         pte = ptep_get(args->ptep);
 148         WARN_ON(pte_write(pte));
 149         ptep_get_and_clear(args->mm, args->vaddr, args->ptep);
 150         pte = ptep_get(args->ptep);
 151         WARN_ON(!pte_none(pte));
 152
 153         pte = pfn_pte(args->pte_pfn, args->page_prot);
 154         pte = pte_wrprotect(pte);
 155         pte = pte_mkclean(pte);
 156         set_pte_at(args->mm, args->vaddr, args->ptep, pte);
 157         flush_dcache_page(page);
 158         pte = pte_mkwrite(pte);
 159         pte = pte_mkdirty(pte);
 160         ptep_set_access_flags(args->vma, args->vaddr, args->ptep, pte, 1);
 161         pte = ptep_get(args->ptep);
 162         WARN_ON(!(pte_write(pte) && pte_dirty(pte)));
 163         ptep_get_and_clear_full(args->mm, args->vaddr, args->ptep, 1);
 164         pte = ptep_get(args->ptep);
 165         WARN_ON(!pte_none(pte));
 166
 167         pte = pfn_pte(args->pte_pfn, args->page_prot);
 168         pte = pte_mkyoung(pte);
 169         set_pte_at(args->mm, args->vaddr, args->ptep, pte);
 170         flush_dcache_page(page);
 171         ptep_test_and_clear_young(args->vma, args->vaddr, args->ptep);
 172         pte = ptep_get(args->ptep);
 173         WARN_ON(pte_young(pte));
 174 }
 175
 176 static void __init pte_savedwrite_tests(struct pgtable_debug_args *args)
 177 {
 178         pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot_none);
 179
 180         if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
 181                 return;
 182
 183         pr_debug("Validating PTE saved write\n");
 184         WARN_ON(!pte_savedwrite(pte_mk_savedwrite(pte_clear_savedwrite(pte))));
 185         WARN_ON(pte_savedwrite(pte_clear_savedwrite(pte_mk_savedwrite(pte))));
 186 }
 187
 188 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 189 static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx)
 190 {
 191         pgprot_t prot = protection_map[idx];
 192         unsigned long val = idx, *ptr = &val;
 193         pmd_t pmd;
 194
 195         if (!has_transparent_hugepage())
 196                 return;
 197
 198         pr_debug("Validating PMD basic (%pGv)\n", ptr);
 199         pmd = pfn_pmd(args->fixed_pmd_pfn, prot);
 200
 201         /*
 202          * This test needs to be executed after the given page table entry
 203          * is created with pfn_pmd() to make sure that protection_map[idx]
 204          * does not have the dirty bit enabled from the beginning. This is
 205          * important for platforms like arm64 where (!PTE_RDONLY) indicate
 206          * dirty bit being set.
 207          */
 208         WARN_ON(pmd_dirty(pmd_wrprotect(pmd)));
 209
 210
 211         WARN_ON(!pmd_same(pmd, pmd));
 212         WARN_ON(!pmd_young(pmd_mkyoung(pmd_mkold(pmd))));
 213         WARN_ON(!pmd_dirty(pmd_mkdirty(pmd_mkclean(pmd))));
 214         WARN_ON(!pmd_write(pmd_mkwrite(pmd_wrprotect(pmd))));
 215         WARN_ON(pmd_young(pmd_mkold(pmd_mkyoung(pmd))));
 216         WARN_ON(pmd_dirty(pmd_mkclean(pmd_mkdirty(pmd))));
 217         WARN_ON(pmd_write(pmd_wrprotect(pmd_mkwrite(pmd))));
 218         WARN_ON(pmd_dirty(pmd_wrprotect(pmd_mkclean(pmd))));
 219         WARN_ON(!pmd_dirty(pmd_wrprotect(pmd_mkdirty(pmd))));
 220         /*
 221          * A huge page does not point to next level page table
 222          * entry. Hence this must qualify as pmd_bad().
 223          */
 224         WARN_ON(!pmd_bad(pmd_mkhuge(pmd)));
 225 }
 226
 227 static void __init pmd_advanced_tests(struct pgtable_debug_args *args)
 228 {
 229         struct page *page;
 230         pmd_t pmd;
 231         unsigned long vaddr = args->vaddr;
 232
 233         if (!has_transparent_hugepage())
 234                 return;
 235
 236         page = (args->pmd_pfn != ULONG_MAX) ? pfn_to_page(args->pmd_pfn) : NULL;
 237         if (!page)
 238                 return;
 239
 240         /*
 241          * flush_dcache_page() is called after set_pmd_at() to clear
 242          * PG_arch_1 for the page on ARM64. The page flag isn't cleared
 243          * when it's released and page allocation check will fail when
 244          * the page is allocated again. For architectures other than ARM64,
 245          * the unexpected overhead of cache flushing is acceptable.
 246          */
 247         pr_debug("Validating PMD advanced\n");
 248         /* Align the address wrt HPAGE_PMD_SIZE */
 249         vaddr &= HPAGE_PMD_MASK;
 250
 251         pgtable_trans_huge_deposit(args->mm, args->pmdp, args->start_ptep);
 252
 253         pmd = pfn_pmd(args->pmd_pfn, args->page_prot);
 254         set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
 255         flush_dcache_page(page);
 256         pmdp_set_wrprotect(args->mm, vaddr, args->pmdp);
 257         pmd = READ_ONCE(*args->pmdp);
 258         WARN_ON(pmd_write(pmd));
 259         pmdp_huge_get_and_clear(args->mm, vaddr, args->pmdp);
 260         pmd = READ_ONCE(*args->pmdp);
 261         WARN_ON(!pmd_none(pmd));
 262
 263         pmd = pfn_pmd(args->pmd_pfn, args->page_prot);
 264         pmd = pmd_wrprotect(pmd);
 265         pmd = pmd_mkclean(pmd);
 266         set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
 267         flush_dcache_page(page);
 268         pmd = pmd_mkwrite(pmd);
 269         pmd = pmd_mkdirty(pmd);
 270         pmdp_set_access_flags(args->vma, vaddr, args->pmdp, pmd, 1);
 271         pmd = READ_ONCE(*args->pmdp);
 272         WARN_ON(!(pmd_write(pmd) && pmd_dirty(pmd)));
 273         pmdp_huge_get_and_clear_full(args->vma, vaddr, args->pmdp, 1);
 274         pmd = READ_ONCE(*args->pmdp);
 275         WARN_ON(!pmd_none(pmd));
 276
 277         pmd = pmd_mkhuge(pfn_pmd(args->pmd_pfn, args->page_prot));
 278         pmd = pmd_mkyoung(pmd);
 279         set_pmd_at(args->mm, vaddr, args->pmdp, pmd);
 280         flush_dcache_page(page);
 281         pmdp_test_and_clear_young(args->vma, vaddr, args->pmdp);
 282         pmd = READ_ONCE(*args->pmdp);
 283         WARN_ON(pmd_young(pmd));
 284
 285         /*  Clear the pte entries  */
 286         pmdp_huge_get_and_clear(args->mm, vaddr, args->pmdp);
 287         pgtable_trans_huge_withdraw(args->mm, args->pmdp);
 288 }
 289
 290 static void __init pmd_leaf_tests(struct pgtable_debug_args *args)
 291 {
 292         pmd_t pmd;
 293
 294         if (!has_transparent_hugepage())
 295                 return;
 296
 297         pr_debug("Validating PMD leaf\n");
 298         pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
 299
 300         /*
 301          * PMD based THP is a leaf entry.
 302          */
 303         pmd = pmd_mkhuge(pmd);
 304         WARN_ON(!pmd_leaf(pmd));
 305 }
 306
 307 static void __init pmd_savedwrite_tests(struct pgtable_debug_args *args)
 308 {
 309         pmd_t pmd;
 310
 311         if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
 312                 return;
 313
 314         if (!has_transparent_hugepage())
 315                 return;
 316
 317         pr_debug("Validating PMD saved write\n");
 318         pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot_none);
 319         WARN_ON(!pmd_savedwrite(pmd_mk_savedwrite(pmd_clear_savedwrite(pmd))));
 320         WARN_ON(pmd_savedwrite(pmd_clear_savedwrite(pmd_mk_savedwrite(pmd))));
 321 }
 322
 323 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 324 static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx)
 325 {
 326         pgprot_t prot = protection_map[idx];
 327         unsigned long val = idx, *ptr = &val;
 328         pud_t pud;
 329
 330         if (!has_transparent_hugepage())
 331                 return;
 332
 333         pr_debug("Validating PUD basic (%pGv)\n", ptr);
 334         pud = pfn_pud(args->fixed_pud_pfn, prot);
 335
 336         /*
 337          * This test needs to be executed after the given page table entry
 338          * is created with pfn_pud() to make sure that protection_map[idx]
 339          * does not have the dirty bit enabled from the beginning. This is
 340          * important for platforms like arm64 where (!PTE_RDONLY) indicate
 341          * dirty bit being set.
 342          */
 343         WARN_ON(pud_dirty(pud_wrprotect(pud)));
 344
 345         WARN_ON(!pud_same(pud, pud));
 346         WARN_ON(!pud_young(pud_mkyoung(pud_mkold(pud))));
 347         WARN_ON(!pud_dirty(pud_mkdirty(pud_mkclean(pud))));
 348         WARN_ON(pud_dirty(pud_mkclean(pud_mkdirty(pud))));
 349         WARN_ON(!pud_write(pud_mkwrite(pud_wrprotect(pud))));
 350         WARN_ON(pud_write(pud_wrprotect(pud_mkwrite(pud))));
 351         WARN_ON(pud_young(pud_mkold(pud_mkyoung(pud))));
 352         WARN_ON(pud_dirty(pud_wrprotect(pud_mkclean(pud))));
 353         WARN_ON(!pud_dirty(pud_wrprotect(pud_mkdirty(pud))));
 354
 355         if (mm_pmd_folded(args->mm))
 356                 return;
 357
 358         /*
 359          * A huge page does not point to next level page table
 360          * entry. Hence this must qualify as pud_bad().
 361          */
 362         WARN_ON(!pud_bad(pud_mkhuge(pud)));
 363 }
 364
 365 static void __init pud_advanced_tests(struct pgtable_debug_args *args)
 366 {
 367         struct page *page;
 368         unsigned long vaddr = args->vaddr;
 369         pud_t pud;
 370
 371         if (!has_transparent_hugepage())
 372                 return;
 373
 374         page = (args->pud_pfn != ULONG_MAX) ? pfn_to_page(args->pud_pfn) : NULL;
 375         if (!page)
 376                 return;
 377
 378         /*
 379          * flush_dcache_page() is called after set_pud_at() to clear
 380          * PG_arch_1 for the page on ARM64. The page flag isn't cleared
 381          * when it's released and page allocation check will fail when
 382          * the page is allocated again. For architectures other than ARM64,
 383          * the unexpected overhead of cache flushing is acceptable.
 384          */
 385         pr_debug("Validating PUD advanced\n");
 386         /* Align the address wrt HPAGE_PUD_SIZE */
 387         vaddr &= HPAGE_PUD_MASK;
 388
 389         pud = pfn_pud(args->pud_pfn, args->page_prot);
 390         set_pud_at(args->mm, vaddr, args->pudp, pud);
 391         flush_dcache_page(page);
 392         pudp_set_wrprotect(args->mm, vaddr, args->pudp);
 393         pud = READ_ONCE(*args->pudp);
 394         WARN_ON(pud_write(pud));
 395
 396 #ifndef __PAGETABLE_PMD_FOLDED
 397         pudp_huge_get_and_clear(args->mm, vaddr, args->pudp);
 398         pud = READ_ONCE(*args->pudp);
 399         WARN_ON(!pud_none(pud));
 400 #endif /* __PAGETABLE_PMD_FOLDED */
 401         pud = pfn_pud(args->pud_pfn, args->page_prot);
 402         pud = pud_wrprotect(pud);
 403         pud = pud_mkclean(pud);
 404         set_pud_at(args->mm, vaddr, args->pudp, pud);
 405         flush_dcache_page(page);
 406         pud = pud_mkwrite(pud);
 407         pud = pud_mkdirty(pud);
 408         pudp_set_access_flags(args->vma, vaddr, args->pudp, pud, 1);
 409         pud = READ_ONCE(*args->pudp);
 410         WARN_ON(!(pud_write(pud) && pud_dirty(pud)));
 411
 412 #ifndef __PAGETABLE_PMD_FOLDED
 413         pudp_huge_get_and_clear_full(args->mm, vaddr, args->pudp, 1);
 414         pud = READ_ONCE(*args->pudp);
 415         WARN_ON(!pud_none(pud));
 416 #endif /* __PAGETABLE_PMD_FOLDED */
 417
 418         pud = pfn_pud(args->pud_pfn, args->page_prot);
 419         pud = pud_mkyoung(pud);
 420         set_pud_at(args->mm, vaddr, args->pudp, pud);
 421         flush_dcache_page(page);
 422         pudp_test_and_clear_young(args->vma, vaddr, args->pudp);
 423         pud = READ_ONCE(*args->pudp);
 424         WARN_ON(pud_young(pud));
 425
 426         pudp_huge_get_and_clear(args->mm, vaddr, args->pudp);
 427 }
 428
 429 static void __init pud_leaf_tests(struct pgtable_debug_args *args)
 430 {
 431         pud_t pud;
 432
 433         if (!has_transparent_hugepage())
 434                 return;
 435
 436         pr_debug("Validating PUD leaf\n");
 437         pud = pfn_pud(args->fixed_pud_pfn, args->page_prot);
 438         /*
 439          * PUD based THP is a leaf entry.
 440          */
 441         pud = pud_mkhuge(pud);
 442         WARN_ON(!pud_leaf(pud));
 443 }
 444 #else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 445 static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx) { }
 446 static void __init pud_advanced_tests(struct pgtable_debug_args *args) { }
 447 static void __init pud_leaf_tests(struct pgtable_debug_args *args) { }
 448 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 449 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
 450 static void __init pmd_basic_tests(struct pgtable_debug_args *args, int idx) { }
 451 static void __init pud_basic_tests(struct pgtable_debug_args *args, int idx) { }
 452 static void __init pmd_advanced_tests(struct pgtable_debug_args *args) { }
 453 static void __init pud_advanced_tests(struct pgtable_debug_args *args) { }
 454 static void __init pmd_leaf_tests(struct pgtable_debug_args *args) { }
 455 static void __init pud_leaf_tests(struct pgtable_debug_args *args) { }
 456 static void __init pmd_savedwrite_tests(struct pgtable_debug_args *args) { }
 457 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 458
 459 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
 460 static void __init pmd_huge_tests(struct pgtable_debug_args *args)
 461 {
 462         pmd_t pmd;
 463
 464         if (!arch_vmap_pmd_supported(args->page_prot))
 465                 return;
 466
 467         pr_debug("Validating PMD huge\n");
 468         /*
 469          * X86 defined pmd_set_huge() verifies that the given
 470          * PMD is not a populated non-leaf entry.
 471          */
 472         WRITE_ONCE(*args->pmdp, __pmd(0));
 473         WARN_ON(!pmd_set_huge(args->pmdp, __pfn_to_phys(args->fixed_pmd_pfn), args->page_prot));
 474         WARN_ON(!pmd_clear_huge(args->pmdp));
 475         pmd = READ_ONCE(*args->pmdp);
 476         WARN_ON(!pmd_none(pmd));
 477 }
 478
 479 static void __init pud_huge_tests(struct pgtable_debug_args *args)
 480 {
 481         pud_t pud;
 482
 483         if (!arch_vmap_pud_supported(args->page_prot))
 484                 return;
 485
 486         pr_debug("Validating PUD huge\n");
 487         /*
 488          * X86 defined pud_set_huge() verifies that the given
 489          * PUD is not a populated non-leaf entry.
 490          */
 491         WRITE_ONCE(*args->pudp, __pud(0));
 492         WARN_ON(!pud_set_huge(args->pudp, __pfn_to_phys(args->fixed_pud_pfn), args->page_prot));
 493         WARN_ON(!pud_clear_huge(args->pudp));
 494         pud = READ_ONCE(*args->pudp);
 495         WARN_ON(!pud_none(pud));
 496 }
 497 #else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */
 498 static void __init pmd_huge_tests(struct pgtable_debug_args *args) { }
 499 static void __init pud_huge_tests(struct pgtable_debug_args *args) { }
 500 #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */
 501
 502 static void __init p4d_basic_tests(struct pgtable_debug_args *args)
 503 {
 504         p4d_t p4d;
 505
 506         pr_debug("Validating P4D basic\n");
 507         memset(&p4d, RANDOM_NZVALUE, sizeof(p4d_t));
 508         WARN_ON(!p4d_same(p4d, p4d));
 509 }
 510
 511 static void __init pgd_basic_tests(struct pgtable_debug_args *args)
 512 {
 513         pgd_t pgd;
 514
 515         pr_debug("Validating PGD basic\n");
 516         memset(&pgd, RANDOM_NZVALUE, sizeof(pgd_t));
 517         WARN_ON(!pgd_same(pgd, pgd));
 518 }
 519
 520 #ifndef __PAGETABLE_PUD_FOLDED
 521 static void __init pud_clear_tests(struct pgtable_debug_args *args)
 522 {
 523         pud_t pud = READ_ONCE(*args->pudp);
 524
 525         if (mm_pmd_folded(args->mm))
 526                 return;
 527
 528         pr_debug("Validating PUD clear\n");
 529         pud = __pud(pud_val(pud) | RANDOM_ORVALUE);
 530         WRITE_ONCE(*args->pudp, pud);
 531         pud_clear(args->pudp);
 532         pud = READ_ONCE(*args->pudp);
 533         WARN_ON(!pud_none(pud));
 534 }
 535
 536 static void __init pud_populate_tests(struct pgtable_debug_args *args)
 537 {
 538         pud_t pud;
 539
 540         if (mm_pmd_folded(args->mm))
 541                 return;
 542
 543         pr_debug("Validating PUD populate\n");
 544         /*
 545          * This entry points to next level page table page.
 546          * Hence this must not qualify as pud_bad().
 547          */
 548         pud_populate(args->mm, args->pudp, args->start_pmdp);
 549         pud = READ_ONCE(*args->pudp);
 550         WARN_ON(pud_bad(pud));
 551 }
 552 #else  /* !__PAGETABLE_PUD_FOLDED */
 553 static void __init pud_clear_tests(struct pgtable_debug_args *args) { }
 554 static void __init pud_populate_tests(struct pgtable_debug_args *args) { }
 555 #endif /* PAGETABLE_PUD_FOLDED */
 556
 557 #ifndef __PAGETABLE_P4D_FOLDED
 558 static void __init p4d_clear_tests(struct pgtable_debug_args *args)
 559 {
 560         p4d_t p4d = READ_ONCE(*args->p4dp);
 561
 562         if (mm_pud_folded(args->mm))
 563                 return;
 564
 565         pr_debug("Validating P4D clear\n");
 566         p4d = __p4d(p4d_val(p4d) | RANDOM_ORVALUE);
 567         WRITE_ONCE(*args->p4dp, p4d);
 568         p4d_clear(args->p4dp);
 569         p4d = READ_ONCE(*args->p4dp);
 570         WARN_ON(!p4d_none(p4d));
 571 }
 572
 573 static void __init p4d_populate_tests(struct pgtable_debug_args *args)
 574 {
 575         p4d_t p4d;
 576
 577         if (mm_pud_folded(args->mm))
 578                 return;
 579
 580         pr_debug("Validating P4D populate\n");
 581         /*
 582          * This entry points to next level page table page.
 583          * Hence this must not qualify as p4d_bad().
 584          */
 585         pud_clear(args->pudp);
 586         p4d_clear(args->p4dp);
 587         p4d_populate(args->mm, args->p4dp, args->start_pudp);
 588         p4d = READ_ONCE(*args->p4dp);
 589         WARN_ON(p4d_bad(p4d));
 590 }
 591
 592 static void __init pgd_clear_tests(struct pgtable_debug_args *args)
 593 {
 594         pgd_t pgd = READ_ONCE(*(args->pgdp));
 595
 596         if (mm_p4d_folded(args->mm))
 597                 return;
 598
 599         pr_debug("Validating PGD clear\n");
 600         pgd = __pgd(pgd_val(pgd) | RANDOM_ORVALUE);
 601         WRITE_ONCE(*args->pgdp, pgd);
 602         pgd_clear(args->pgdp);
 603         pgd = READ_ONCE(*args->pgdp);
 604         WARN_ON(!pgd_none(pgd));
 605 }
 606
 607 static void __init pgd_populate_tests(struct pgtable_debug_args *args)
 608 {
 609         pgd_t pgd;
 610
 611         if (mm_p4d_folded(args->mm))
 612                 return;
 613
 614         pr_debug("Validating PGD populate\n");
 615         /*
 616          * This entry points to next level page table page.
 617          * Hence this must not qualify as pgd_bad().
 618          */
 619         p4d_clear(args->p4dp);
 620         pgd_clear(args->pgdp);
 621         pgd_populate(args->mm, args->pgdp, args->start_p4dp);
 622         pgd = READ_ONCE(*args->pgdp);
 623         WARN_ON(pgd_bad(pgd));
 624 }
 625 #else  /* !__PAGETABLE_P4D_FOLDED */
 626 static void __init p4d_clear_tests(struct pgtable_debug_args *args) { }
 627 static void __init pgd_clear_tests(struct pgtable_debug_args *args) { }
 628 static void __init p4d_populate_tests(struct pgtable_debug_args *args) { }
 629 static void __init pgd_populate_tests(struct pgtable_debug_args *args) { }
 630 #endif /* PAGETABLE_P4D_FOLDED */
 631
 632 static void __init pte_clear_tests(struct pgtable_debug_args *args)
 633 {
 634         struct page *page;
 635         pte_t pte = pfn_pte(args->pte_pfn, args->page_prot);
 636
 637         page = (args->pte_pfn != ULONG_MAX) ? pfn_to_page(args->pte_pfn) : NULL;
 638         if (!page)
 639                 return;
 640
 641         /*
 642          * flush_dcache_page() is called after set_pte_at() to clear
 643          * PG_arch_1 for the page on ARM64. The page flag isn't cleared
 644          * when it's released and page allocation check will fail when
 645          * the page is allocated again. For architectures other than ARM64,
 646          * the unexpected overhead of cache flushing is acceptable.
 647          */
 648         pr_debug("Validating PTE clear\n");
 649 #ifndef CONFIG_RISCV
 650         pte = __pte(pte_val(pte) | RANDOM_ORVALUE);
 651 #endif
 652         set_pte_at(args->mm, args->vaddr, args->ptep, pte);
 653         flush_dcache_page(page);
 654         barrier();
 655         pte_clear(args->mm, args->vaddr, args->ptep);
 656         pte = ptep_get(args->ptep);
 657         WARN_ON(!pte_none(pte));
 658 }
 659
 660 static void __init pmd_clear_tests(struct pgtable_debug_args *args)
 661 {
 662         pmd_t pmd = READ_ONCE(*args->pmdp);
 663
 664         pr_debug("Validating PMD clear\n");
 665         pmd = __pmd(pmd_val(pmd) | RANDOM_ORVALUE);
 666         WRITE_ONCE(*args->pmdp, pmd);
 667         pmd_clear(args->pmdp);
 668         pmd = READ_ONCE(*args->pmdp);
 669         WARN_ON(!pmd_none(pmd));
 670 }
 671
 672 static void __init pmd_populate_tests(struct pgtable_debug_args *args)
 673 {
 674         pmd_t pmd;
 675
 676         pr_debug("Validating PMD populate\n");
 677         /*
 678          * This entry points to next level page table page.
 679          * Hence this must not qualify as pmd_bad().
 680          */
 681         pmd_populate(args->mm, args->pmdp, args->start_ptep);
 682         pmd = READ_ONCE(*args->pmdp);
 683         WARN_ON(pmd_bad(pmd));
 684 }
 685
 686 static void __init pte_special_tests(struct pgtable_debug_args *args)
 687 {
 688         pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
 689
 690         if (!IS_ENABLED(CONFIG_ARCH_HAS_PTE_SPECIAL))
 691                 return;
 692
 693         pr_debug("Validating PTE special\n");
 694         WARN_ON(!pte_special(pte_mkspecial(pte)));
 695 }
 696
 697 static void __init pte_protnone_tests(struct pgtable_debug_args *args)
 698 {
 699         pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot_none);
 700
 701         if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
 702                 return;
 703
 704         pr_debug("Validating PTE protnone\n");
 705         WARN_ON(!pte_protnone(pte));
 706         WARN_ON(!pte_present(pte));
 707 }
 708
 709 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 710 static void __init pmd_protnone_tests(struct pgtable_debug_args *args)
 711 {
 712         pmd_t pmd;
 713
 714         if (!IS_ENABLED(CONFIG_NUMA_BALANCING))
 715                 return;
 716
 717         if (!has_transparent_hugepage())
 718                 return;
 719
 720         pr_debug("Validating PMD protnone\n");
 721         pmd = pmd_mkhuge(pfn_pmd(args->fixed_pmd_pfn, args->page_prot_none));
 722         WARN_ON(!pmd_protnone(pmd));
 723         WARN_ON(!pmd_present(pmd));
 724 }
 725 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
 726 static void __init pmd_protnone_tests(struct pgtable_debug_args *args) { }
 727 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 728
 729 #ifdef CONFIG_ARCH_HAS_PTE_DEVMAP
 730 static void __init pte_devmap_tests(struct pgtable_debug_args *args)
 731 {
 732         pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
 733
 734         pr_debug("Validating PTE devmap\n");
 735         WARN_ON(!pte_devmap(pte_mkdevmap(pte)));
 736 }
 737
 738 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 739 static void __init pmd_devmap_tests(struct pgtable_debug_args *args)
 740 {
 741         pmd_t pmd;
 742
 743         if (!has_transparent_hugepage())
 744                 return;
 745
 746         pr_debug("Validating PMD devmap\n");
 747         pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
 748         WARN_ON(!pmd_devmap(pmd_mkdevmap(pmd)));
 749 }
 750
 751 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 752 static void __init pud_devmap_tests(struct pgtable_debug_args *args)
 753 {
 754         pud_t pud;
 755
 756         if (!has_transparent_hugepage())
 757                 return;
 758
 759         pr_debug("Validating PUD devmap\n");
 760         pud = pfn_pud(args->fixed_pud_pfn, args->page_prot);
 761         WARN_ON(!pud_devmap(pud_mkdevmap(pud)));
 762 }
 763 #else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 764 static void __init pud_devmap_tests(struct pgtable_debug_args *args) { }
 765 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 766 #else  /* CONFIG_TRANSPARENT_HUGEPAGE */
 767 static void __init pmd_devmap_tests(struct pgtable_debug_args *args) { }
 768 static void __init pud_devmap_tests(struct pgtable_debug_args *args) { }
 769 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 770 #else
 771 static void __init pte_devmap_tests(struct pgtable_debug_args *args) { }
 772 static void __init pmd_devmap_tests(struct pgtable_debug_args *args) { }
 773 static void __init pud_devmap_tests(struct pgtable_debug_args *args) { }
 774 #endif /* CONFIG_ARCH_HAS_PTE_DEVMAP */
 775
 776 static void __init pte_soft_dirty_tests(struct pgtable_debug_args *args)
 777 {
 778         pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
 779
 780         if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
 781                 return;
 782
 783         pr_debug("Validating PTE soft dirty\n");
 784         WARN_ON(!pte_soft_dirty(pte_mksoft_dirty(pte)));
 785         WARN_ON(pte_soft_dirty(pte_clear_soft_dirty(pte)));
 786 }
 787
 788 static void __init pte_swap_soft_dirty_tests(struct pgtable_debug_args *args)
 789 {
 790         pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
 791
 792         if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
 793                 return;
 794
 795         pr_debug("Validating PTE swap soft dirty\n");
 796         WARN_ON(!pte_swp_soft_dirty(pte_swp_mksoft_dirty(pte)));
 797         WARN_ON(pte_swp_soft_dirty(pte_swp_clear_soft_dirty(pte)));
 798 }
 799
 800 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 801 static void __init pmd_soft_dirty_tests(struct pgtable_debug_args *args)
 802 {
 803         pmd_t pmd;
 804
 805         if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY))
 806                 return;
 807
 808         if (!has_transparent_hugepage())
 809                 return;
 810
 811         pr_debug("Validating PMD soft dirty\n");
 812         pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
 813         WARN_ON(!pmd_soft_dirty(pmd_mksoft_dirty(pmd)));
 814         WARN_ON(pmd_soft_dirty(pmd_clear_soft_dirty(pmd)));
 815 }
 816
 817 static void __init pmd_swap_soft_dirty_tests(struct pgtable_debug_args *args)
 818 {
 819         pmd_t pmd;
 820
 821         if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY) ||
 822                 !IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION))
 823                 return;
 824
 825         if (!has_transparent_hugepage())
 826                 return;
 827
 828         pr_debug("Validating PMD swap soft dirty\n");
 829         pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
 830         WARN_ON(!pmd_swp_soft_dirty(pmd_swp_mksoft_dirty(pmd)));
 831         WARN_ON(pmd_swp_soft_dirty(pmd_swp_clear_soft_dirty(pmd)));
 832 }
 833 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
 834 static void __init pmd_soft_dirty_tests(struct pgtable_debug_args *args) { }
 835 static void __init pmd_swap_soft_dirty_tests(struct pgtable_debug_args *args) { }
 836 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 837
 838 static void __init pte_swap_tests(struct pgtable_debug_args *args)
 839 {
 840         swp_entry_t swp;
 841         pte_t pte;
 842
 843         pr_debug("Validating PTE swap\n");
 844         pte = pfn_pte(args->fixed_pte_pfn, args->page_prot);
 845         swp = __pte_to_swp_entry(pte);
 846         pte = __swp_entry_to_pte(swp);
 847         WARN_ON(args->fixed_pte_pfn != pte_pfn(pte));
 848 }
 849
 850 #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION
 851 static void __init pmd_swap_tests(struct pgtable_debug_args *args)
 852 {
 853         swp_entry_t swp;
 854         pmd_t pmd;
 855
 856         if (!has_transparent_hugepage())
 857                 return;
 858
 859         pr_debug("Validating PMD swap\n");
 860         pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
 861         swp = __pmd_to_swp_entry(pmd);
 862         pmd = __swp_entry_to_pmd(swp);
 863         WARN_ON(args->fixed_pmd_pfn != pmd_pfn(pmd));
 864 }
 865 #else  /* !CONFIG_ARCH_ENABLE_THP_MIGRATION */
 866 static void __init pmd_swap_tests(struct pgtable_debug_args *args) { }
 867 #endif /* CONFIG_ARCH_ENABLE_THP_MIGRATION */
 868
 869 static void __init swap_migration_tests(struct pgtable_debug_args *args)
 870 {
 871         struct page *page;
 872         swp_entry_t swp;
 873
 874         if (!IS_ENABLED(CONFIG_MIGRATION))
 875                 return;
 876
 877         /*
 878          * swap_migration_tests() requires a dedicated page as it needs to
 879          * be locked before creating a migration entry from it. Locking the
 880          * page that actually maps kernel text ('start_kernel') can be real
 881          * problematic. Lets use the allocated page explicitly for this
 882          * purpose.
 883          */
 884         page = (args->pte_pfn != ULONG_MAX) ? pfn_to_page(args->pte_pfn) : NULL;
 885         if (!page)
 886                 return;
 887
 888         pr_debug("Validating swap migration\n");
 889
 890         /*
 891          * make_migration_entry() expects given page to be
 892          * locked, otherwise it stumbles upon a BUG_ON().
 893          */
 894         __SetPageLocked(page);
 895         swp = make_writable_migration_entry(page_to_pfn(page));
 896         WARN_ON(!is_migration_entry(swp));
 897         WARN_ON(!is_writable_migration_entry(swp));
 898
 899         swp = make_readable_migration_entry(swp_offset(swp));
 900         WARN_ON(!is_migration_entry(swp));
 901         WARN_ON(is_writable_migration_entry(swp));
 902
 903         swp = make_readable_migration_entry(page_to_pfn(page));
 904         WARN_ON(!is_migration_entry(swp));
 905         WARN_ON(is_writable_migration_entry(swp));
 906         __ClearPageLocked(page);
 907 }
 908
 909 #ifdef CONFIG_HUGETLB_PAGE
 910 static void __init hugetlb_basic_tests(struct pgtable_debug_args *args)
 911 {
 912         struct page *page;
 913         pte_t pte;
 914
 915         pr_debug("Validating HugeTLB basic\n");
 916         /*
 917          * Accessing the page associated with the pfn is safe here,
 918          * as it was previously derived from a real kernel symbol.
 919          */
 920         page = pfn_to_page(args->fixed_pmd_pfn);
 921         pte = mk_huge_pte(page, args->page_prot);
 922
 923         WARN_ON(!huge_pte_dirty(huge_pte_mkdirty(pte)));
 924         WARN_ON(!huge_pte_write(huge_pte_mkwrite(huge_pte_wrprotect(pte))));
 925         WARN_ON(huge_pte_write(huge_pte_wrprotect(huge_pte_mkwrite(pte))));
 926
 927 #ifdef CONFIG_ARCH_WANT_GENERAL_HUGETLB
 928         pte = pfn_pte(args->fixed_pmd_pfn, args->page_prot);
 929
 930         WARN_ON(!pte_huge(pte_mkhuge(pte)));
 931 #endif /* CONFIG_ARCH_WANT_GENERAL_HUGETLB */
 932 }
 933 #else  /* !CONFIG_HUGETLB_PAGE */
 934 static void __init hugetlb_basic_tests(struct pgtable_debug_args *args) { }
 935 #endif /* CONFIG_HUGETLB_PAGE */
 936
 937 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 938 static void __init pmd_thp_tests(struct pgtable_debug_args *args)
 939 {
 940         pmd_t pmd;
 941
 942         if (!has_transparent_hugepage())
 943                 return;
 944
 945         pr_debug("Validating PMD based THP\n");
 946         /*
 947          * pmd_trans_huge() and pmd_present() must return positive after
 948          * MMU invalidation with pmd_mkinvalid(). This behavior is an
 949          * optimization for transparent huge page. pmd_trans_huge() must
 950          * be true if pmd_page() returns a valid THP to avoid taking the
 951          * pmd_lock when others walk over non transhuge pmds (i.e. there
 952          * are no THP allocated). Especially when splitting a THP and
 953          * removing the present bit from the pmd, pmd_trans_huge() still
 954          * needs to return true. pmd_present() should be true whenever
 955          * pmd_trans_huge() returns true.
 956          */
 957         pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot);
 958         WARN_ON(!pmd_trans_huge(pmd_mkhuge(pmd)));
 959
 960 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
 961         WARN_ON(!pmd_trans_huge(pmd_mkinvalid(pmd_mkhuge(pmd))));
 962         WARN_ON(!pmd_present(pmd_mkinvalid(pmd_mkhuge(pmd))));
 963 #endif /* __HAVE_ARCH_PMDP_INVALIDATE */
 964 }
 965
 966 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 967 static void __init pud_thp_tests(struct pgtable_debug_args *args)
 968 {
 969         pud_t pud;
 970
 971         if (!has_transparent_hugepage())
 972                 return;
 973
 974         pr_debug("Validating PUD based THP\n");
 975         pud = pfn_pud(args->fixed_pud_pfn, args->page_prot);
 976         WARN_ON(!pud_trans_huge(pud_mkhuge(pud)));
 977
 978         /*
 979          * pud_mkinvalid() has been dropped for now. Enable back
 980          * these tests when it comes back with a modified pud_present().
 981          *
 982          * WARN_ON(!pud_trans_huge(pud_mkinvalid(pud_mkhuge(pud))));
 983          * WARN_ON(!pud_present(pud_mkinvalid(pud_mkhuge(pud))));
 984          */
 985 }
 986 #else  /* !CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 987 static void __init pud_thp_tests(struct pgtable_debug_args *args) { }
 988 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
 989 #else  /* !CONFIG_TRANSPARENT_HUGEPAGE */
 990 static void __init pmd_thp_tests(struct pgtable_debug_args *args) { }
 991 static void __init pud_thp_tests(struct pgtable_debug_args *args) { }
 992 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 993
 994 static unsigned long __init get_random_vaddr(void)
 995 {
 996         unsigned long random_vaddr, random_pages, total_user_pages;
 997
 998         total_user_pages = (TASK_SIZE - FIRST_USER_ADDRESS) / PAGE_SIZE;
 999
1000         random_pages = get_random_long() % total_user_pages;
1001         random_vaddr = FIRST_USER_ADDRESS + random_pages * PAGE_SIZE;
1002
1003         return random_vaddr;
1004 }
1005
1006 static void __init destroy_args(struct pgtable_debug_args *args)
1007 {
1008         struct page *page = NULL;
1009
1010         /* Free (huge) page */
1011         if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
1012             IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) &&
1013             has_transparent_hugepage() &&
1014             args->pud_pfn != ULONG_MAX) {
1015                 if (args->is_contiguous_page) {
1016                         free_contig_range(args->pud_pfn,
1017                                           (1 << (HPAGE_PUD_SHIFT - PAGE_SHIFT)));
1018                 } else {
1019                         page = pfn_to_page(args->pud_pfn);
1020                         __free_pages(page, HPAGE_PUD_SHIFT - PAGE_SHIFT);
1021                 }
1022
1023                 args->pud_pfn = ULONG_MAX;
1024                 args->pmd_pfn = ULONG_MAX;
1025                 args->pte_pfn = ULONG_MAX;
1026         }
1027
1028         if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
1029             has_transparent_hugepage() &&
1030             args->pmd_pfn != ULONG_MAX) {
1031                 if (args->is_contiguous_page) {
1032                         free_contig_range(args->pmd_pfn, (1 << HPAGE_PMD_ORDER));
1033                 } else {
1034                         page = pfn_to_page(args->pmd_pfn);
1035                         __free_pages(page, HPAGE_PMD_ORDER);
1036                 }
1037
1038                 args->pmd_pfn = ULONG_MAX;
1039                 args->pte_pfn = ULONG_MAX;
1040         }
1041
1042         if (args->pte_pfn != ULONG_MAX) {
1043                 page = pfn_to_page(args->pte_pfn);
1044                 __free_pages(page, 0);
1045
1046                 args->pte_pfn = ULONG_MAX;
1047         }
1048
1049         /* Free page table entries */
1050         if (args->start_ptep) {
1051                 pte_free(args->mm, args->start_ptep);
1052                 mm_dec_nr_ptes(args->mm);
1053         }
1054
1055         if (args->start_pmdp) {
1056                 pmd_free(args->mm, args->start_pmdp);
1057                 mm_dec_nr_pmds(args->mm);
1058         }
1059
1060         if (args->start_pudp) {
1061                 pud_free(args->mm, args->start_pudp);
1062                 mm_dec_nr_puds(args->mm);
1063         }
1064
1065         if (args->start_p4dp)
1066                 p4d_free(args->mm, args->start_p4dp);
1067
1068         /* Free vma and mm struct */
1069         if (args->vma)
1070                 vm_area_free(args->vma);
1071
1072         if (args->mm)
1073                 mmdrop(args->mm);
1074 }
1075
1076 static struct page * __init
1077 debug_vm_pgtable_alloc_huge_page(struct pgtable_debug_args *args, int order)
1078 {
1079         struct page *page = NULL;
1080
1081 #ifdef CONFIG_CONTIG_ALLOC
1082         if (order >= MAX_ORDER) {
1083                 page = alloc_contig_pages((1 << order), GFP_KERNEL,
1084                                           first_online_node, NULL);
1085                 if (page) {
1086                         args->is_contiguous_page = true;
1087                         return page;
1088                 }
1089         }
1090 #endif
1091
1092         if (order < MAX_ORDER)
1093                 page = alloc_pages(GFP_KERNEL, order);
1094
1095         return page;
1096 }
1097
1098 static int __init init_args(struct pgtable_debug_args *args)
1099 {
1100         struct page *page = NULL;
1101         phys_addr_t phys;
1102         int ret = 0;
1103
1104         /*
1105          * Initialize the debugging data.
1106          *
1107          * __P000 (or even __S000) will help create page table entries with
1108          * PROT_NONE permission as required for pxx_protnone_tests().
1109          */
1110         memset(args, 0, sizeof(*args));
1111         args->vaddr              = get_random_vaddr();
1112         args->page_prot          = vm_get_page_prot(VMFLAGS);
1113         args->page_prot_none     = __P000;
1114         args->is_contiguous_page = false;
1115         args->pud_pfn            = ULONG_MAX;
1116         args->pmd_pfn            = ULONG_MAX;
1117         args->pte_pfn            = ULONG_MAX;
1118         args->fixed_pgd_pfn      = ULONG_MAX;
1119         args->fixed_p4d_pfn      = ULONG_MAX;
1120         args->fixed_pud_pfn      = ULONG_MAX;
1121         args->fixed_pmd_pfn      = ULONG_MAX;
1122         args->fixed_pte_pfn      = ULONG_MAX;
1123
1124         /* Allocate mm and vma */
1125         args->mm = mm_alloc();
1126         if (!args->mm) {
1127                 pr_err("Failed to allocate mm struct\n");
1128                 ret = -ENOMEM;
1129                 goto error;
1130         }
1131
1132         args->vma = vm_area_alloc(args->mm);
1133         if (!args->vma) {
1134                 pr_err("Failed to allocate vma\n");
1135                 ret = -ENOMEM;
1136                 goto error;
1137         }
1138
1139         /*
1140          * Allocate page table entries. They will be modified in the tests.
1141          * Lets save the page table entries so that they can be released
1142          * when the tests are completed.
1143          */
1144         args->pgdp = pgd_offset(args->mm, args->vaddr);
1145         args->p4dp = p4d_alloc(args->mm, args->pgdp, args->vaddr);
1146         if (!args->p4dp) {
1147                 pr_err("Failed to allocate p4d entries\n");
1148                 ret = -ENOMEM;
1149                 goto error;
1150         }
1151         args->start_p4dp = p4d_offset(args->pgdp, 0UL);
1152         WARN_ON(!args->start_p4dp);
1153
1154         args->pudp = pud_alloc(args->mm, args->p4dp, args->vaddr);
1155         if (!args->pudp) {
1156                 pr_err("Failed to allocate pud entries\n");
1157                 ret = -ENOMEM;
1158                 goto error;
1159         }
1160         args->start_pudp = pud_offset(args->p4dp, 0UL);
1161         WARN_ON(!args->start_pudp);
1162
1163         args->pmdp = pmd_alloc(args->mm, args->pudp, args->vaddr);
1164         if (!args->pmdp) {
1165                 pr_err("Failed to allocate pmd entries\n");
1166                 ret = -ENOMEM;
1167                 goto error;
1168         }
1169         args->start_pmdp = pmd_offset(args->pudp, 0UL);
1170         WARN_ON(!args->start_pmdp);
1171
1172         if (pte_alloc(args->mm, args->pmdp)) {
1173                 pr_err("Failed to allocate pte entries\n");
1174                 ret = -ENOMEM;
1175                 goto error;
1176         }
1177         args->start_ptep = pmd_pgtable(READ_ONCE(*args->pmdp));
1178         WARN_ON(!args->start_ptep);
1179
1180         /*
1181          * PFN for mapping at PTE level is determined from a standard kernel
1182          * text symbol. But pfns for higher page table levels are derived by
1183          * masking lower bits of this real pfn. These derived pfns might not
1184          * exist on the platform but that does not really matter as pfn_pxx()
1185          * helpers will still create appropriate entries for the test. This
1186          * helps avoid large memory block allocations to be used for mapping
1187          * at higher page table levels in some of the tests.
1188          */
1189         phys = __pa_symbol(&start_kernel);
1190         args->fixed_pgd_pfn = __phys_to_pfn(phys & PGDIR_MASK);
1191         args->fixed_p4d_pfn = __phys_to_pfn(phys & P4D_MASK);
1192         args->fixed_pud_pfn = __phys_to_pfn(phys & PUD_MASK);
1193         args->fixed_pmd_pfn = __phys_to_pfn(phys & PMD_MASK);
1194         args->fixed_pte_pfn = __phys_to_pfn(phys & PAGE_MASK);
1195         WARN_ON(!pfn_valid(args->fixed_pte_pfn));
1196
1197         /*
1198          * Allocate (huge) pages because some of the tests need to access
1199          * the data in the pages. The corresponding tests will be skipped
1200          * if we fail to allocate (huge) pages.
1201          */
1202         if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
1203             IS_ENABLED(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) &&
1204             has_transparent_hugepage()) {
1205                 page = debug_vm_pgtable_alloc_huge_page(args,
1206                                 HPAGE_PUD_SHIFT - PAGE_SHIFT);
1207                 if (page) {
1208                         args->pud_pfn = page_to_pfn(page);
1209                         args->pmd_pfn = args->pud_pfn;
1210                         args->pte_pfn = args->pud_pfn;
1211                         return 0;
1212                 }
1213         }
1214
1215         if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE) &&
1216             has_transparent_hugepage()) {
1217                 page = debug_vm_pgtable_alloc_huge_page(args, HPAGE_PMD_ORDER);
1218                 if (page) {
1219                         args->pmd_pfn = page_to_pfn(page);
1220                         args->pte_pfn = args->pmd_pfn;
1221                         return 0;
1222                 }
1223         }
1224
1225         page = alloc_pages(GFP_KERNEL, 0);
1226         if (page)
1227                 args->pte_pfn = page_to_pfn(page);
1228
1229         return 0;
1230
1231 error:
1232         destroy_args(args);
1233         return ret;
1234 }
1235
1236 static int __init debug_vm_pgtable(void)
1237 {
1238         struct pgtable_debug_args args;
1239         spinlock_t *ptl = NULL;
1240         int idx, ret;
1241
1242         pr_info("Validating architecture page table helpers\n");
1243         ret = init_args(&args);
1244         if (ret)
1245                 return ret;
1246
1247         /*
1248          * Iterate over the protection_map[] to make sure that all
1249          * the basic page table transformation validations just hold
1250          * true irrespective of the starting protection value for a
1251          * given page table entry.
1252          */
1253         for (idx = 0; idx < ARRAY_SIZE(protection_map); idx++) {
1254                 pte_basic_tests(&args, idx);
1255                 pmd_basic_tests(&args, idx);
1256                 pud_basic_tests(&args, idx);
1257         }
1258
1259         /*
1260          * Both P4D and PGD level tests are very basic which do not
1261          * involve creating page table entries from the protection
1262          * value and the given pfn. Hence just keep them out from
1263          * the above iteration for now to save some test execution
1264          * time.
1265          */
1266         p4d_basic_tests(&args);
1267         pgd_basic_tests(&args);
1268
1269         pmd_leaf_tests(&args);
1270         pud_leaf_tests(&args);
1271
1272         pte_savedwrite_tests(&args);
1273         pmd_savedwrite_tests(&args);
1274
1275         pte_special_tests(&args);
1276         pte_protnone_tests(&args);
1277         pmd_protnone_tests(&args);
1278
1279         pte_devmap_tests(&args);
1280         pmd_devmap_tests(&args);
1281         pud_devmap_tests(&args);
1282
1283         pte_soft_dirty_tests(&args);
1284         pmd_soft_dirty_tests(&args);
1285         pte_swap_soft_dirty_tests(&args);
1286         pmd_swap_soft_dirty_tests(&args);
1287
1288         pte_swap_tests(&args);
1289         pmd_swap_tests(&args);
1290
1291         swap_migration_tests(&args);
1292
1293         pmd_thp_tests(&args);
1294         pud_thp_tests(&args);
1295
1296         hugetlb_basic_tests(&args);
1297
1298         /*
1299          * Page table modifying tests. They need to hold
1300          * proper page table lock.
1301          */
1302
1303         args.ptep = pte_offset_map_lock(args.mm, args.pmdp, args.vaddr, &ptl);
1304         pte_clear_tests(&args);
1305         pte_advanced_tests(&args);
1306         pte_unmap_unlock(args.ptep, ptl);
1307
1308         ptl = pmd_lock(args.mm, args.pmdp);
1309         pmd_clear_tests(&args);
1310         pmd_advanced_tests(&args);
1311         pmd_huge_tests(&args);
1312         pmd_populate_tests(&args);
1313         spin_unlock(ptl);
1314
1315         ptl = pud_lock(args.mm, args.pudp);
1316         pud_clear_tests(&args);
1317         pud_advanced_tests(&args);
1318         pud_huge_tests(&args);
1319         pud_populate_tests(&args);
1320         spin_unlock(ptl);
1321
1322         spin_lock(&(args.mm->page_table_lock));
1323         p4d_clear_tests(&args);
1324         pgd_clear_tests(&args);
1325         p4d_populate_tests(&args);
1326         pgd_populate_tests(&args);
1327         spin_unlock(&(args.mm->page_table_lock));
1328
1329         destroy_args(&args);
1330         return 0;
1331 }
1332 late_initcall(debug_vm_pgtable);